Insect repellents



Patented Feb. 3, 1953 UNITED STATES "PATENT OFFICE INSE CT BEPELLENT S No Drawing. Original application January=11, 1949, Serial. No. 70,384. Divided and this applicationv August 30, 1950, Serial No. 187,832

11 Claims.

This application is a division of our application Serial No. 70,384, filed January 11, 1949, for Insect Repellents (now abandoned).

This invention relates to insect repellents.

We have found that the applicationof a monoester of a saturated fatty acid and-a saturated parafiinic (alkyl), including cycloparafiinic, diol, when applied to the hum-an skin or to a fabric, effectively repels insects, particularly A'des aegypti and anopheles quadrimaculatus. These monoesters may be represented by the general general formula I-IOROAc wherein R represents the residue of a paraffin having an open or a closed chain, and Ac represents the acyl residue of a saturated fatty acid having from 3 to 7 carbon atoms inclusive, the sum of the carbon atoms in the R and Ac group being at least 8.

Examples of diols whoseesterification products are insectrepellents within the scope of this invention are, for instance, glycol, p-ropanediol, pentanediol, hexanediol, nonanediol, cyclohexanediol; among suitable esterifying acids are, for instance, acetic acid, propionic acid, butyric acid, pivalic acid, caproic acid, enanthic acid.

Tests to measure the repellency of the abovementioned compounds against insects by skin application were conducted ,by smearing the compound on the, arms of test personneLwho then thrust their arms into cages containing insects.

The arms were exposed for 30-minute intervals at 3 minutes each until the first insect bite.

Tests to measure the repellency of fabrics impregnated with the above-mentioned compounds against insects were conducted by uniformly impregnating mercerized cotton hose with the compound at a rate equivalent to 3.3, gms. per sq. 'ft., drawing the dried hose over the arms of test personnel, who then thrust their covered arms into cages containing insects for 1 to 2 minutes. If no bites or less than bites were received, the tests were repeated each successive day until 5 or more bites during one exposure were received.

The following table illustrates the results obtained by the above test methods against A'des aegyptz' and Anopheles quadrzmaculatus, as examples of insects against which the invention is applicable, by using compounds in accordance with the present invention:

a. MONOESTERS Insect llcplellctncy pp Insect Repelto Skin lency of Material F1111:preinatedt a no gains- Ades i ag g? Ades aegypm' aegypti g a culatus Mins. Mi'ns. glycol monocaproate 200 over 10 days. 1,2-pr0pancdiol monocapro- 209 80 Do.

e. 1,3-propanediolm0nocapro- 207 37 Do.

a 1,5-pe11tanediol monopro- 216 53 Do.

pionate. 1,51pentanedi0l monoenan- 262 32 at least 1 day.

tiate. l,3 cyclohexanediol mon0- 250 69 over 10 days.

propiouatc. 1,3-cyclohexanediol mono- 267 67 D0.

butyrate.

b. DIES TE RS 1,5-pcntanediol dipropio- 170 98 nate. 1,5-pentanedi01 dipivalate. 259 over 10 days. l,9-nonanediol diacetate..- 224 at least 1 day. 1,3-cyclohexanediol diace- 216 72 Do.

tate.

The esters contemplated by the present invention may be prepared by reacting (usually refluxing) the diol with acid or-acid anhydride or acyl chloride, preferably in the presence of a Catalyst e. g., ,toluenesulfonic acid. In the case of-a monoester, the diol is present in excess, while for a diester an excess (at least 2 mols) of acid or acyl chloride are used in the reaction mixtureper 1 mol of (1101.

The following examples illustrate the preparation of several typical compounds enumerated in the above table:

Example 1 GOgms. of glycol (about 1 mol) are reacted with 60 gms. of caproic acid (about .5 mol) in the presence of 100 cc. of chloroform. The reaction product is washed and distilled; the yield is 40 gms. of glycol 'monocaproate, a liquid boiling at C. at .3 mm. pressure and having a, refractive index of n =l.4=308.

Example 2 40 gms. of 1,2-propanedio1 and 84.5 gms. of

caproic anhydride are refluxed in the presence of 100 cc. of toluene. The reaction products, namely caproic acid and 1,2-propanediol monocaproate, are separated by distilaltion. 36 gms. of 1,2- propanediol monocaproate are obtained, a liquid boiling at 77 C. at .3 mm. pressure and havin a refractive index of n =1.4326.

Example 3 40 gms. of enanthyl chloride (prepared by reacting 50 gms. of enanthic acid and 47 gms. of thionyl chloride) are reacted with 34 gms. of pentanediol to the presence of 79 gms. of pyridine. The yield is 51 gms. of 1,5-pentanediol monoenanthate, a liquid boiling at 119 C. at .2 mm. pressure and having a refractive index of n =1.4439.

Example 4 60 gms. of 1,3-cyclohexanediol are reacted with 36.9 gms. of butyryl chloride in the presence of 79 gms. of pyridine. The yield is 43 gms. of 1,3- cyclohexanediol monobutyrate, a liquid boiling at 98 C. at .2 mm. pressure and having a refractive index of 1 =1.4594.v

Example 5 Example 6 35 gms. of 1,9-nonanediol are reacted with 50 gms. of acetic anhydride in the presence of toluene. The yield is 41 gms. o-f 1,9-nonanediol diacetate, a liquid boiling at 107 C. at .2 mm. pressure and having a refractive index of n =1.4359. Example 7 30 gms. of 1,3-cyclohexanediol (.26 mol) are reacted with 41 gms. of acetyl chloride (.52 mol) in the presence of '79 gms. of pyridine. The yield is 38 gms. of 1,3-cyclohexanediol diacetate, a liquid boiling at 83 C. at a pressure of under 1 mm. and having a refractive index of For ease of application the compounds contemplated by the present invention may b incorporated in a suitable inert liquid or solid carrier such as mineral oil, alcohol, petrolatum, etc. For facile and uniform fabric impregnation, they may be applied in an inert solvent, such as alcohol, ether, etc.

Having thus described our invention,

We claim:

1. A process of rendering a fabric insect repellent comprising impregnating said fabric with 1,3cyclohexanediol monopropionate.

2. An Ae'des aegypti repellent fabric comprising fabric impregnated with a monoester, said monoester being the esterification product of a saturated fatty acid having from 3 to 7 carbon atoms inclusive and of a member of the group 4 consisting of 1,5-pentanediol and 1,3-cyclohexanediol.

3. An A'des aeqypti repellent fabric comprising fabric impregnated with 1,5-pentanediol monopropionate.

4. An insect repellent fabric comprising fabric impregnated with 1,3-cyclohexanediol monopropionate.

5. A process of repelling insects comprising applying 1,3-cyclohexanediol monopropionate to the skin.

6. An A'des aegypti repellent fabric comprising fabric impregnated with a monoester having at least 8 carbon atoms, said monester being the esterification product of a paraflinic, including cycloparaffini-c diol and of a saturated fatty acid having from 3 to 7 carbon atoms inclusive.

'7. An Ae'des aegyptz' repellent composition comprising, in a non-gaseous inert organic carrier, a monoester having at least 8 carbon atoms, said monoester being the esterification product of a paraffinic, including cycloparaffinic diol and of a saturated fatty acid having from 3 to 7 carbon atoms inclusive.

8. An A'des aegyptz' repellent composition comprising, in a non-gaseous inert organic carrier, a monoester, said monoester being the esterification product of a saturated fatty acid having from 3 to 7 carbon atoms inclusive and of a member of the group consisting of 1,5-pentanediol and 1,3-cyclohexanediol.

9. The monoesters of a saturated fatty acid having from 3 to 7 carbon atoms inclusive and of cyclohexane diol.

10. An Aedes aegypti repellent composition comprising pentanediol monopropionate in a non-gaseons inert organic carrier.

11. An insect repellent composition comprising cyclohexanediol monopropionate in a nongaseous inert organic carrier.

NATHAN L. DRAKE. SIDNEY MELAMED;

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,302,159 Wasum Nov. 17, 1942 2,446,505 Arenson Aug. 3, 1948 OTHER REFERENCES Linduska et al.,F1ea repellents for use on clothing. J. Econ. Entomology, vol. 39, No. 6, December 1946, pages 767-769. Entries: Laurie acid, propylene glycol monoester; and propionic acid, pentamethylene diester.

Newman et a1., Some new compounds as possible insect repellents. J. A. C. 8., vol 68, October 1946, pages 2112-2115. Entries: Ethylene glycol mono (n) valerate, and 1,2-propylene glycol, monophenylacetate.

Beilstein, vol. VI, pages 739-741.

Beilstein, vol. VI, 2nd supplement (1944), pages 743-749.

Beilstein, Handbuch der organischen Chemie, vol. II (1920) pages 272 and 313.

OSRD Insect Control Committee Report No. 28, Interim Report No. 0-94, May 18, 1945. Esp. page 38, 0-6311, Phenoxyacetic acid, 1,3-propanediol monoester. 

1. A PROCESS OF RENDERING A FABRIC INSECT REPELLENT COMPRISING IMPREGNATING SAID FABRIC WITH 1,3-CYCLOHEXANEDIOL MONOPROPIONATE. 